Section 2: Metabolic Diseases of Ruminants: Hypocalcemia (Donovan) Flashcards Preview

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Flashcards in Section 2: Metabolic Diseases of Ruminants: Hypocalcemia (Donovan) Deck (25):
1

metabolic disease

derangement of metabolic process

2

milk fever =

hypocalcemia

3

predisposing factors for hypocalcemia in cows

>4 yrs old
high milk production
inappetence
low exercise
high stress (i.e. calving, hormonal changes)
Jersey breed
prepartum diet high in Calcium or has a positive DCAD

4

When does HC usually occur?

at parturition. Ca requirement surges just prior to parturition, and more Ca is taken up from blood pool for lactational demand. Results in loss from bone, urine, fetus

5

During HC, there is decreased Ca input from:

-Bone (older cows and/or +DCAD)
-Diet (decreased intake or absorption)

6

3 hormones/vitamins involved in Ca metabolism*********

1) PTH (+)
2) Vit. D (+)
3) Thyrocalcitonin (-)

7

What happens if pre-partum diet is high in Ca? ***

thyrocalcitonin is upregulated, which inhibits bone mobilization of Ca. Also inhibits PTH, so bone mobilization and intestinal absorption of Ca cannot be activated. Activation of active form of vit. D in kidney is inhibited.

8

How is vit. D from sun transformed in the body?

turned into inactive form in liver, then active form is produced in the kidney under influence of PTH

9

fx of active vit D

increases absorption of Ca and bone mobilization

10

clinical signs of early stage milk fever

-off feed
-staggering
-protrusion of tongue
-normal temp
-fast HR

11

excitement stage of milk fever

-severe ataxia
-muscle tremors
-dilated pupils
-faster HR
-dry/scant feces
-rumen stasis
-body temp variable

12

recumbent stage of milk fever

-sternal recumb.
-loss of reflexes
-S neck (unique to milk fever!)
-fast HR
-temp variable

13

unconscious stage of milk fever

-lat. recumb.
-groaning
-bloat!
-no reflexes
-HR 100-120, weak

14

Ddx of milk fever

-no test
-good PE
-response to tx: calcium salt IV (preferred) or oral calcium gel

15

HC prevention

Dietary manipulation during last 3 wks of gestation:
1) Ca restriction (trad. method) or
2) negative DCAD

16

result of Ca restriction physiologically ***

No calcitonin produced, so PTH not inhibited. PTH stimulates bone mobilization of Ca and stimulates kidney to make active vit. D which also promotes bone mobilization and intestinal absorption of Ca

17

DCAD =

(Na+ + K+) - (Cl- + S-)

18

normal cow diets are neg/pos. charged

pos

19

how does neg. DCAD prevent milk fever? ***

-induces mild metabolic acidosis
-decreased pH upregulates of PTH receptors in kidney, so it takes less PTH to induce reaction to transform inactive vit. D to active vit. D
-cow also releases bone buffer, which helps maintain Ca lvls in the blood by drawing out Ca with it

20

anionic salts you can add to diet to make neg. DCAD

MgSO4, CaSO4, CaCl2, MgCl2, NH4Cl

21

HC is a major risk factor for all of the following cattle diseases:

-prolapsed uterus
-retained placenta
-early metritis
-rumen stasis
-ketosis
-DA
-peripartum immune dysfunction
-down cow syndrome

22

REVIEW SLIDE 35 FLOWCHART

:)

23

insufficient dietary effective fiber can cause:

rumen acidosis, lameness, DA

24

decreased DMI around calving can cause:

neg. energy/protein balance --> ketosis/fatty liver

25

stages of HC in order

1) early stage
2) excitement stage
3) recumbent stage
4) unconscious stage